The stock is soaring in extended trading. It’s up more than 5% after Google reported its earnings.

The average cost that advertisers pay every time users clicked on ads is stabilizing. That number has been falling dramatically in recent quarters because of the increase in mobile ads, but in the fourth quarter cost-per-click fell only 6% on-year and even rose 2% from the third quarter.

The most recent quarter is an interesting one in Google’s history, as there is a bit of a disconnect between Google and investors. Google had to come out and remind investors and analysts that its Motorola Home portion would not be included with its standard account. Here was what Google earlier this month:

For example, as of this writing, a majority of Wall Street analysts who cover Google have not reflected the Home business as discontinued operations in their estimates.

Q4 revenue would have been $15.24 billion had Motorola Home been included, Google said.

Here are a few takeaways from Google’s earnings:

Cost-per-click continues to fall, but it’s stabilizing. It decreased approximately 6% over the fourth quarter of 2011 and increased approximately 2% over the third quarter of 2012. This could be attributable to the overwhelming shift to mobile devices, which is also affecting companies like Facebook and Zynga. Google’s CPC fell 15% year-over-year in the third quarter.

Still, Google’s advertising revenue is up. “Advertising and other” revenue amounted to $12.9 billion, up about 22% year-over-year in the fourth quarter. Paid clicks increased about 24% in Q4 year-over-year and 9% quarter-over-quarter.

Motorola Mobility brought in $1.51 billion in revenue. Google is reportedly working on a “Google X” phone, so we may soon see the fruits of its Motorola Mobility acquisition. Non-GAAP operating loss for Motorola Mobile in the fourth quarter of 2012 was $152 million.

“Other costs of revenue” shows a particular spike. Other costs increased to $3.14 billion, or 22% of revenues, in Q4 2012, up from $1.25 billion, or 12% of revenues, in the Q4 2011. Chief financial officer Patrick Pichette said Google’s increase in “other costs of revenue” was driven by content acquisition costs and hardware costs related to Google Play.

Google is still plowing through Motorola’s pipeline. There are 12 to 18 months worth of product pipeline that Google has to get through after its acquisition of Motorola Mobility.